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G Gaudreault

Publications and source records attributed to G Gaudreault.

3 recordsLinked to original sources
PubMed1992

[Measurement of cardiac output by Doppler echocardiography at the 4 cardiac valves].

Many observers remain sceptical with regards to the utilization of Doppler-echocardiographic measurements of intracardiac outputs for the quantification of shunts and regurgitations. In this context, we evaluated the feasibility and validity of measuring output at the level of the four cardiac valves in a population of 35 normal subjects (24 M, 12 F) aged from 23 to 37 years (mean +/- SD = 28 +/- 4). Measurement of stroke volume and output using predetermined criteria was possible in the aortic position in 35 (100%) subjects, in the mitral position in 34 (97%), in the pulmonary position in 20 (57%) and in the tricuspid position in 10 (29%). In 14 subjects (40%), measurement was possible at 2 sites, in 14 (40%) at 3 sites and in 7 (20%) at 4 sites. Inability to measure output was most often due to poor visualization of valvular annulus. There are excellent correlations between aortic stroke volume on the one hand and the mitral (r = 0.97, SEE = 3.41 cc), pulmonary (r = 0.97, SEE = 3.69 cc) and tricuspid (r = 0.96, SEE = 2.77 cc) stroke volumes respectively on the other. These results suggest that reliable measurements of output are feasible in a majority of cases in the aortic and mitral positions but to a much more limited extent in the pulmonary and tricuspid positions; given the small SEE's, they should be useful to quantitate shunts and regurgitations, when feasible.

Adult↗
PubMed1991

Use of Valsalva maneuver to unmask left ventricular diastolic function abnormalities by Doppler echocardiography in patients with coronary artery disease or systemic hypertension.

It has been suggested that changes in left atrial pressure may mask or mimic left ventricular diastolic function abnormalities detected by Doppler echocardiography. The effect of the Valsalva maneuver on the transmitral flow velocity profile was therefore studied in 28 patients without evidence of coronary artery disease (group 1, mean age +/- standard deviation 50 +/- 8 years) and in 94 patients with evidence of coronary artery disease or systemic hypertension (group 2, mean age 54 +/- 10 years). At baseline, group 2 patients had higher peak late diastolic filling velocity (A), lower peak early (E) to late diastolic filling velocity (E/A) ratio and longer isovolumic relaxation time than group 1, whereas heart rate, E velocity and E deceleration time were similar in both groups. During Valsalva, both groups had similar increases in heart rate and similar decreases in E velocity but E/A ratio decreased significantly only in group 2 because of a lesser decrease in A velocity. The E/A ratio was greater than or equal to 1.0 both before and during Valsalva in all but 1 patient in group 1, whereas in group 2, 32 patients had E/A greater than or equal to 1.0 at rest and during Valsalva, 33 patients had E/A greater than or equal to 1.0 at rest but less than 1.0 both at rest and during Valsalva. Using group 1 as controls, prevalence, specificity and positive predictive value of E/A less than 1.0 in group 2 were 31, 100 and 100% at rest and 66, 96 and 98% during Valsalva.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗